Electric control device



Jan. 4, 1966 E. A. KAMP 3,227,979

ELECTRIC CONTROL DEVICE Filed March 13, 1963 2 Sheets-Sheet 1 M Zia FIGJ Fl 2 W, XML W94 Iva/24x75,

Jan. 4, 1966 E. A. KAMP ELECTRIC CONTROL DEVICE 2 Sheets-Sheet 2 Filed March 15, 1965 M P M W 1/ 6 a a M w 9 IIIII K )7 n lil w hll ll M m w M M 4 i m z M M W a 2 a M m H w M 6 6 a, (ml/M m g m z 2 a Q w W 6 w 0 m a 3 MM 7 W m W fl M W M w w 5 "m M, Q Q o mug 3 W L United States Patent 3,227,979 ELECTRIC CONTROL DEVICE Earl A. Kamp, Jackson, Mo., assignor to Mar-Amp, Inc., Jackson, Mo., a corporation of Missouri Filed Mar. 13, 1963, Ser. No. 264,855 3 Claims. (Cl. 336133) The present invention relates generally to control de vices and more particularly to a control device for use with welding instruments and the like.

Many control devices have been devised and employed heretofore to control and to adjust current flow to an electrical instrument such as a welding or soldering instrument, a battery charger or a similar device. The known devices, however, are relatively complicated and expensive to make, are limited in use, are relatively inaccurate, and are relatively difiicult and time consuming to adjust and operate. Furthermore, most of the known devices provide incremental selection of outputs rather than smooth adjustment to any place within the range thereof.

These and other shortcomings and disadvantages of known devices are overcome by the present device which comprises a control device including a core structure having two pairs of spaced connected legs forming a closed magnetic path around a core opening, a winding mounted on each leg of one of said pairs of legs, one of said windings including inductively coupled primary and secondary portions, means for connecting the primary winding portion to an energy source, means connecting the secondary winding portion in circuit with a selected portion of the winding on the other core leg of said pair of legs across an instrument to be con-trolled, and means for varying the magnetic coupling between said last named connected windings to vary the output to the controlled instrument, said means including a fifth core leg positioned between the windings on said pair of spaced legs and extending across the core opening between the other pair of spaced core legs, and means for moving said fifth core leg transversely in the core opening to vary the magnetic coupling between the said windings, said last named means including a spiral shaped member rotatably mounted adjacent to said core and operatively connected to said fifth leg.

It is a principal object of the present invention to provide simple and relatively inexpensive means to vary the output of an electrical control device.

Another object is to provide means for adjusting the output of an electromagnetic device to any condition within the range thereof.

Another object is to provide improved means for varying the magnetic characteristics of a core structure.

Another object is to provide a versatile electromagnetic control device capable of supplying power to many different kinds of loads.

Another object is to provide improved means for adjusting the magnetic coupling between spaced windings mounted on a core structure.

Another object is to provide improved means for accurately adjusting an output current to an instrument such as an arc welding tool, a welding or soldering gun, a battery charger or some other similar or related device.

ice

These and other objects and advantages of the present invention will become apparent after considering the following detailed description of several embodiments thereof in conjunction with the accompanying drawings, where- 1n:

FIG. 1 is a sectional side elevational view of an electromagnetic control device constructed according to the present invention;

FIG. 2 is a cross-sectional view taken on line 22 of FIG. 1;

FIG. 3 is a perspective view of an instrument embodying the principles of the present invention;

FIG. 4 is an enlarged fragmentary perspective view of a movable core member and associated operating mechanism therefor;

FIG. 5 is a schematic wiring diagram showing a typical circuit for the subject device, and

FIG. 6 is a view similar to FIG. 1 showing a modified form of the subject device.

Referring to the drawings by reference numbers, the number 10 is an electromagnetic control device constructed according to the present invention. The device 10 is housed in a casing 12 which is substantially closed on all sides including top and bottom. The front panel 14 of the casing 12 serves as a control panel for the device. An on-off switch 16, a plurality of plug-in receptacles which will be described later, an operator output adjustment means 18, and a meter for use when the device is operating as a battery charger are all mounted on the control panel 14 and will be described more in detail hereinafter.

The device 10 includes a closed four leg core structure 24 (FIG. 1) centrally positioned in the casing 12 and supported therein by pairs of spaced horizontal non-magnetic angle members 26 and 28. The core 24 is constructed of a plurality of stacked laminations 24a appropriately arranged to form a closed magnetic path defined by spaced pairs of core legs. The upper and lower horizontal core legs 30 and 32 respectively are clamped by the pairs of angle members 26 and 28, and the vertical core legs identified by numbers 34 and 36 have windings 38 and 40 respectively mounted thereon.

The windings 38 on the leg 34 includes mutually inductively coupled primary and secondary winding portions 42 and 44 as illustrated schematically in FIG. 5. The primary winding portion 42 is provided with input leads 46 and 47 for connection to an alternating current source 48 and the secondary winding portion 44, or a preselected portion thereof, is connected in a circuit with a selected portion of the winding 40 mounted on the leg 36. The series combination of the windings 40 and 44 is then connected to a welding instrument or other load through the plug-in receptacles located on the front panel 14.

Two of the plug-in receptacles 50 and 52 labeled Low Range are used for arc welding at relatively low welding current and are plugged by a cable connector 54 attached to the ends of leads 56 and 58. The opposite ends of the leads 56 and 58 are connected to clips (not shown) which are attached to an arc welding rod and to a device to be welded. The receptacle 50 is connected by a lead 64 inside the housing 12 to an intermediate location on the secondary winding 44, and the receptacle 52 is connected by a lead 66 to one end of winding portion 3 4011 which is part of the winding 40 (FIG. When the connector 54 is plugged into receptacles 5t) and 52 arc welding can be performed at any welding current within a relatively low range as will be shown.

In similar manner High Range receptacles 68 and 70 are provided and can also be plugged by the cable connector 54 when relatively higher arc welding currents are required. The receptacle 68 is connected by lead 72 to one end of the secondary winding 44, and the receptacle 741 is connected by lead 74 to an intermediate location on the winding portion dill]. It will also be noted in FIG. 5 that one end of the secondary winding 44 is connected to one end of the winding portion 4011 by a lead 76, and the opposite end of the winding portion 40a is connected to the corresponding end of winding portion 40b by a lead 78. When the cable connector 54 is plugged into the high range receptacles 68 and 70 a higher range welding current is available than when plugged into the low range receptacles 50 and 52. The spacing between the receptacles 54 and 52 is the same as the spacing between the receptacles 68 and 70 to enable the same twoprong connector 54 to be plugged into both pairs of receptacles. One advantage of using a two-prong cable connector is that it can only be plugged into the intended receptacles and therefore avoids erroneous connections. It is contemplated, however, that individual cable connectors could also be used if desired. It has been found in practice that two properly selected ranges of welding current outputs are adequate for most purposes. However, additional ranges can be provided by providing additional receptacles connected to other winding locations without departing from the scope of the invention.

Two other receptacles S0 and 82 are also provided on the panel 14 for plugging in individual cable connectors such as the connector 83 (FIG. 3) which is attached to a spot weld gun (not shown). The receptacle 80 is connected by lead 84 to an intermediate point on the secondary winding 44, and the receptacle $2 is connected by lead 86 to an intermediate location on the winding portion 400.

Two receptacles 88 and 90 are also provided for plugging in cable connectors for a soldering instrument. These receptacles supply energy to a carbon piece supported in a holding device which is used to solder light gauge metals and for other relatively low temperature operations. The soldering receptacle 88 is connected by lead 92 to an intermediate location on the winding portion 40b, and the receptacle 90 is connected by lead 94 to the lead 74 that goes to the high range receptacle 70. The spacing between the receptacles 38 and 90 is diiferent from that between the receptacles S0 and 52 and between receptacles 68 and 7 0 to prevent accidentally plugging the cable connector for the gun into the wrong receptacles. As a further precaution the receptacles for different purposes can also be made in different sizes and shapes.

In addition to the above named receptacles, two receptacles 96 and d8 are also provided for connecting a battery charging circuit. The receptacle 96 is connected by lead 100 to one side of the meter 20. The opposite side of the meter 20 is connected by lead 102 to a circuit breaker or switch 104 which is in turn connected by lead 106 to parallel connected rectifiers 103 and 110. The opposite sides of the rectifiers are connected to the low range receptacle lead 66 as shown in FIG. 5. The other battery charger receptacle 98 is connected by lead 112 to the high range receptacle lead 74. To recharge a battery, the battery terminals (not shown) are connected by suitable cables to the receptacles 96 and 98.

The winding 4-0 employed in the subject device is in the nature of an impedance device connected in series with all or a portion of the secondary winding 44, and is electromagnetically coupled thereto by being mounted on the same core 24. If the core 24 were simply a closed core, the coupling between the windings 38 and 46) would be fairly substantial.

The present invention, however, teaches the construction and operation of novel means to vary the coupling between the windings 33 and 40, and hence also the impedance of the winding 40 and the output current. The novel means includes mounting a movable fifth core member or leg 114 in the core window 116 between the upper and lower core legs 30 and 32. In this position the leg 114 is also between the windings 38 and 40. The member 114 like the core structure itself is of laminated construction and the ends thereof extend to adjacent the core legs 30 and 32. The fifth core member 114 is slidably mounted for transverse movement in the core window 116 by non-magnetizable track members 118 and 12! which are connected by a vertical portion 122. The members 118, 120 and 122 are preferably of one piece construction although separate connected pieces could be used. In the structure shown the laminations of the movable fifth leg 114 are oriented perpendicular to the main core laminations to simplify its construction by making all of the laminations thereof have squared ends. The center laminations of the fifth leg are shorter than the outer laminations and form therewith end slots that slidably receive and cooperate with the track members 118 and 120. The construction of the member 114 is clearly shown in FIGS. 2 and 4.

The track members 118 and 120 extend transversely through the core window 116 and are held in position by bolts 124 that extend through openings in the core support members 26 and 28. The track members 118 and 120 extend outwardly from one side of the core structure 24 to provide a fairly wide range of movement for the leg member 114. The ends of the fifth leg member 114 preferably extend to relatively close to the core legs 30 and 32 and the slotted end portions of the movable core member 114 are large enough to move without binding the track members 118 and 120. The closer the ends of the member 114 come to the legs 30 and 32 the wider will be the range of adjustability.

A ring or eyelet member 125 is attached to one side of the movable core leg 114 at an intermediate location. The eyelet 126 receives a rotatable spiral shaped member 128 that is rotated by a shaft 130 journaled at one end to the vertical member 122. The spiral member is shaped like an Archimedean spiral which is defined in Websters Unabridged Dictionary, Second Edition, as being a plane curve generated by a point moving away from or toward a fixed point at a constant rate while the radius vector from the fixed point rotates at a constant rate. This is illustrated in FIGS. 2 and 4. The spiral shaped member 128 and the shaft 130 are preferably made integral to minimize the number of parts and to simplify the construction as shown in FIG. 4. The shaft 130 extends from the journal connection on the member 122 through an opening in the control panel 14, and the front end of the shaft 130 has a control knob 132 attached thereto. The control knob 132 is adjacent to the control panel 14 and is in front of a dial 134 mounted on the panel 14. The knob 132 has a pointer 136 that moves adjacent to the dial 134 when the knob is turned. The dial 134 has two different range scales inscribed on it, one for the high output range and one for the low output range. Inasmuch as two different ranges of output currents are sufficient to cover most welding operations the two adjacent scales are all that are usually required. More scales, however, could be included if additional ranges are needed as already noted.

Once an operator has ascertained the desired welding current for a particular operation, he plugs the cable connector 54 into the appropriate high or low range receptacles. He also sets the knob 132 to the precise desired current setting in the selected scale. When the operator turns the knob 132 the spiral member 128 rotates and moves longitudinally through the eyelet 126 moving the leg 114 transversely in the core window 116. By moving the leg 114 transversely in the core window 116, the flux linking the legs 34 and 36 will vary. For example, when the movable leg 114 is in alignment laterally with the main core 24 considerable flux will bypass the leg 36 and will instead be established in the movable leg 114. This means relatively less flux will be established in the leg 36 to effect a reduction in the effective impedance of the winding 40. The winding 40 will therefore constitute a relatively high impedance in series with the secondary winding portion 44 and hence will reduce the output current to the welding instrument. As the knob 132 is turned the leg 114 will move out of lateral alignment with the core structure 24, thereby reducing the amount of flux passing through the leg 114 and proportionately increasing the flux linking the core legs 34 and 36. This in turn Will decrease the impedance of winding 40 and increase the output current. With this arrangement it is therefore possible to quickly, easily and precisely adjust the output. The scale 134 is calibrated to give the exact value of the output for every position of the knob 132.

Whenever the movable leg 114 is out of lateral registration or alignment with the main core 24 magnetic attraction between it and the main core will operate on it to try to pull it into lateral alignment and out of adjustment. To overcome this undesirable magnetic condition, the shaft 130 on which the spiral 128 is mounted is provided with a serrated member 138. The serrated member 138 is fixedly attached to the shaft 130 and is positioned Within a U-shaped bracket member 140 that is fastened to the side of the member 122. A spring 142 is also positioned on the shaft 130 between the serrated member 138 and the member 122 to urge the serrated member 138- on the shaft forwardly in the device toward the control panel is shown in FIG. 1. The serrated member 138 also has a smooth annular beveled portion 144 to the left of the serrations. A second serrated member 146 is also mounted in the bracket 140, and the serrations on the members 138 and 146 normally cooperate as shown in FIGS. 1 and 4. However, in FIG. 4 it can clearly be seen that the member 146 is pivotally mounted off center on a shaft 148 with the larger portion thereof being positioned on the outer side of the member 138. With this construction the member 146 engages the member 138 and prevents the shaft 130 from turning in a direction to allow the movable leg 114 to move into the core windows 116.

However, when an adjustment is to be made which requires that the movable leg 114 move in a direction into the core 24, the operator simply pushes in on the knob 132 and turns the knob to the desired setting. When the knob 132 is pushed in the spring 142 yields and the serrated member 146 moves into engagement with the smoothed bevel portion 144 of the member 138 to disengage the serrations in the members 138 and 146 and enable rotation of the knob.

A modified form of the device is shown in FIG. 6. The modified construction 200 has a drive motor 202 mounted inside the casing 204 which is operatively connected to the spiral shaft 206 by a gear chain 208, a drive sprocket 210, a chain 212, and a driven sprocket 214. One of the cables 216 that connects the device to an arc welding instrument or the like is provided with a second lead 218 that is connected at one end to the drive motor 202 and at the opposite end to a control switch 220. The shaft 206 is connected to a control knob 222 through a clutch mechanism 224, one part of which is connected to the knob 122 and another part of which is connected to the drive shaft 206. A spring 226 is also provided for releasably engaging the clutch 224. When the knob 222 is pulled out and turned to a desired setting the switch 220 can be actuated to energize the motor 202 to turn the shaft 206 to the desired setting. When the shaft reaches the desired setting the clutch disengages to prevent further shaft turning. The clutch can be replaced by a second switch device or a relay if 6 desired which will open to de-enei'gize the motor 202 when the desired setting is reached. Except for the power drive and the clutch which enables adjustments to be made at the job rather than at the instrument itself, the modified construction is similar in most respects to the construction already described. It should be noted, however, in the modified construction, that the motor 202 and gear chain serves as a brake eliminating the need for serrated members. The modified device is particularly useful where several different preselected outputs are required on a particular job. The modified construction 200 is otherwise operated by plugging cable connectors into desired receptacles as already described.

It is not intended to limit the arrangement of the receptacles to the particular arrangement disclosed since many other arrangements are possible. One such possible arrangement includes having one receptacle that is common for all welding operations in which case only a single other receptacle is required for each different welding range.

It should also be apparent that the output adjustment means including the movable core members can be used to effect changes in the output to a welding instrument, a battery charger circuit, a spot welding gun, a soldering device, or any other device requiring a similar power source. It is important therefore for each different use to be sure that the knob 132 is in the desired position.

Thus there has been shown and described novel control means for producing a desired output current for a device such as a welding instrument, a battery charger, or many other devices including novel means for predeterminately changing the output, which means fulfills all of the objects and advantages sought therefor. Many changes, modifications, variations and other uses of the subject device, however, will become apparent to those skilled in the art after considering this specification and the accompanying drawings. All such changes, modifications, variations and other uses which do not depart from the spirit and scope of the invention are deemed covered by the invention which is limited only by the claims which follow.

What is claimed is:

1. A control device comprising a core structure of closed configuration defined by first and second pairs of spaced connected legs, a winding on both legs of said first pair of spaced legs, means for connecting one of said windings to an alternating current source, and means for varying the coupling between said windings, said last named means including a fifth leg member positioned extending between intermediate locations on the said second pair of spaced core legs across the structure, means for laterally moving said fifth leg member relative to the core structure to vary the magnetic coupling between the core windings, said fifth leg member having transverse grooves in the opposite ends thereof, said fifth leg moving means including track forming means positioned extend ing through the transverse leg end grooves and attached to the said second pair of spaced core legs to form a sliding connection between the fifth leg and the core structure, and a spiral shaped rotatable member slidably engageable with said fifth leg member for moving said fifth leg member along the track means in response to rotation thereof.

2. The control device defined in claim 1 wherein a knob member is provided for rotating said spiral shaped member, said knob member having a pointer thereon movable adjacent to a scale calibrated to indicate output from said device in terms of the position of the fifth leg member relative to the core structure.

3. An electrogmagnetic control device for supplying electric current to a device comprising a laminated core structure defining a closed magnetic path around a core window, a pair of spaced windings mounted on the core structure on opposite legs of the core window, means connecting one of said windings to a source of electric energy, means connecting another of said windings to a device to be supplied with current, a laminated magnetic leg member positioned extending across the core window between the spaced windings, the laminations of said leg member being oriented at right angles to the laminations of said core structure, non-magnetic track means mounted extending transversely of said core window adjacent to an other pair of spaced core legs, some of said leg member laminations being shorter than others to define track receiving grooves in the ends thereof, and means for laterally moving said leg member in the core Window to vary the magnetic coupling between the spaced windings, said moving means including a rotatable elongated Archimedean spiral shaped member and means on said member during movements thereof.

References Cited by the Examiner UNITED STATES PATENTS Hallberg 336-133 X Miller 336-133 X Holslag 336-133 X Schroder 336-133 X Candy 336-133 Lavet 336-133 Wiancko 336-133 X Shuler et a1. 320-2 Mills 336-133 X ROBERT K. SCHAEFER, Primary Examiner.

leg member slidably engageable with said spiral shaped 15 JOHN F. BURNS, WALTER M. ASBURY,

Assistant Examiners. 

1. A CONTROL DEVICE COMPRISING A CORE STRUCTURE OF CLOSED CONFIGURATION DEFINED BY FIRST AND SECOND PAIRS OF SPACED CONNECTED LEGS, A WINDING ON BOTH LEGS OF SAID FIRST PAIR OF SPACED LEGS, MEANS FOR CONNECTING ONE OF SAID WINDINGS TO AN ALTERNATING CURRENT SOURCE, AND MEANS FOR VARYING THE COUPLING BETWEEN SAID WINDINGS, SAID LAST NAMED MEANS INCLUDING A FIFTH LEG MEMBER POSITIONED EXTENDING BETWEEN INTERMEDIATE LOCATIONS ON THE SAID SECOND PAIR OF SPACED CORE LEGS ACROSS THE STRUCTURE, MEANS FOR LATERALLY MOVING SAID FIFTH LEG MEMBER RELATIVE TO THE CORE STUCTURE TO VARY THE MAGNETIC COUPLING BETWEEN THE CORE WINDINGS, SAID FIFTH LEG MEMBER HAVING TRANSVERSE GROOVES IN THE OPPOSITE ENDS THEREOF, SAID FIFTH LEG MOVING MEANS INCLUDING TRACK FORMING MEANS POSITIONED EXTENDING THROUGH THE TRANSVERSE LEG END GROOVES AND ATTACHED TO THE SAID SECOND PAIR OF SPACED CORE LEGS TO FORM A SLIDING CONNECTION BETWEEN THE FIFTH LEG AND THE CORE STRUCTURE, AND A SPIRAL SHAPED ROTATABLE MEMBER SLIDABLY ENGAGEABLE WITH SAID FIFTH LEG MEMBER FOR MOVING SAID FIFTH LEG MEMBER ALONG THE TRACK MEANS IN RESPONSE TO ROTATION THEREOF. 